Dynamic Operation and Control Strategy of Absorption Chiller under Different Working Conditions

Since absorption chillers are nonlinear and strongly coupled, it is difficult to build accurate mechanism models. Based on the experimental data, SVM method is utilized to identify the model of the absorption refrigeration system, which only contains input and output data. The correlation coefficient of the SVM model is more than 0.99 and the mean square error is less than 0.1%. The outlet temperature of the chilled water of the system is controlled by the model-free adaptive control method for system with time delay and PID algorithm respectively to suit for variable load demand. Simulation experiments are carried out in matlab. The results indicate that the established model can be used for control. Compared with the traditional PID algorithm, the absorption chiller under model-free adaptive control algorithm has stronger robustness and respond faster under different working conditions or when desired output is changed, which is more suitable to work under variable load working conditions, and has better transient performance under disturbances or when required load changes. After that, iterative learning control is combined with the model-free adaptive control method to improve the transient performance of the system. A new idea is put forward for the energy-saving controlscheme of absorption chillers.